Hi C*,
Just to confirm I got it right:
- old ADIRU standard uses VS/GS to calculate FPA
- new ADIRU standard uses AoA and pitch/roll only
correct?
No,
Both uses Vzbi/GS to calculate FPA in normal operations.
If no Air Data is available (all ADR OFF/FAIL/FROZEN) the FPA is also not available.
In the L4.2 standard however the FPV returns as
hybrid FPA when ALL ADRs are selected OFF (this action results in BUSS activation).
Honeywell calls data
hybrid if GPS is involved, so I assume the hybrid FPA is based on IR and GPS data.
- does it mean that the new ADIRU references the FPA to the air, or is it somehow corrected for wind?
FPAair is used to calculate wind.
- What's inertial altitude? Is that integrated Vzbi?
See diagram, inertial altitude = hBI :
